Procedure for Spread Plate Technique: A: Serial Dilution. Pipette out 0.1 ml from the appropriate desired dilution series onto the center of the surface of an agar plate. Dip the L-shaped glass spreader (hockey stick). Some do this to be sure things are sterilized, until you are sure the flame has gone out or you will light your alcohol. The serial dilution method involves a stepwise dilution of a substance in solution. Generally the dilution factor at each step is constant. It helps to reduce a dense culture of cells to a more usable concentration. A specific amount of bacteria are reduced with every dilution.
According to the video on the proper aseptic techniques for use in a laboratory, one reason that aseptic technique is necessary is to protect oneself from contact with biohazards that exist within a lab setting. Additionally, it serves the purpose to protect samples from being contaminated. Aseptic technique is also extremely important for safeguarding others in the lab.
Since bacteria are everywhere, including on all of the lab equipment, aseptic techniques allow us to avoid the spread of infection in the above ways. The concentration of bleach that is used to disinfect your work area is a 10% concentration of bleach. The bleach concentration serves as a disinfectant, which is an agent that is intended to kill or remove microorganisms, but it does not kill bacteria spores. It is not a method of sterilization because sterilization is the process used to remove all life forms, including bacteria spores. It is important to disinfect your work area before and after working. Do not trust that the person before you took the time to follow disinfection procedure, so always be sure to be consistent just in case.
Download busta paga pdf editabile gratis. The video demonstrates the need for the step of passing the mouth of the tube through the flame. This is in order to keep the tube free of contamination. The increased temperature at the mouth of the tube works to create a confection-oven-like current, which pushes the air out of the tube and eliminates the potential for airborne contaminants to get into the mouth of the tube. The presence of the Bunsen Burner in the lab area also serves to decrease the amount of airborne contamination, but this process ensures that anything that may still be present in the air does not enter the tube.
The correct way to successfully perform this procedure is to pass the tube over the flame at a 45-degree angle. A pure culture is a culture that only has one type of microorganism growing in it. As a result, if you only see one type of microorganism growing in the culture, then you know that you have used the aseptic technique correctly and have achieves a pure culture. However, if you see one or more microorganisms growing in the culture, then you have created a mixed culture, and somewhere along the way the aseptic technique was likely not performed correctly, allowing for some type of contamination of another microorganism. If this happens, you should perform the process over again using the aseptic technique until your results yield a pure culture. The serial dilution agar plate technique is when you dilute a sample several times to achieve several different dilutions. For example, if you are working with a urine sample that you need to test for the presence of microorganisms.